*/
#include "private.h"
#include <ccan/likely/likely.h>
+#include <ccan/ilog/ilog.h>
#include <time.h>
#include <assert.h>
#include <limits.h>
static unsigned fls64(uint64_t val)
{
-#if HAVE_BUILTIN_CLZL
- if (val <= ULONG_MAX) {
- /* This is significantly faster! */
- return val ? sizeof(long) * CHAR_BIT - __builtin_clzl(val) : 0;
- } else {
-#endif
- uint64_t r = 64;
-
- if (!val)
- return 0;
- if (!(val & 0xffffffff00000000ull)) {
- val <<= 32;
- r -= 32;
- }
- if (!(val & 0xffff000000000000ull)) {
- val <<= 16;
- r -= 16;
- }
- if (!(val & 0xff00000000000000ull)) {
- val <<= 8;
- r -= 8;
- }
- if (!(val & 0xf000000000000000ull)) {
- val <<= 4;
- r -= 4;
- }
- if (!(val & 0xc000000000000000ull)) {
- val <<= 2;
- r -= 2;
- }
- if (!(val & 0x8000000000000000ull)) {
- val <<= 1;
- r -= 1;
- }
- return r;
-#if HAVE_BUILTIN_CLZL
- }
-#endif
+ return ilog64(val);
}
/* In which bucket would we find a particular record size? (ignoring header) */
-unsigned int size_to_bucket(unsigned int zone_bits, tdb_len_t data_len)
+unsigned int size_to_bucket(tdb_len_t data_len)
{
unsigned int bucket;
bucket = fls64(data_len - TDB_MIN_DATA_LEN) + 2;
}
- if (unlikely(bucket > BUCKETS_FOR_ZONE(zone_bits)))
- bucket = BUCKETS_FOR_ZONE(zone_bits);
+ if (unlikely(bucket >= TDB_FREE_BUCKETS))
+ bucket = TDB_FREE_BUCKETS - 1;
return bucket;
}
-/* Subtract 1-byte tailer and header. Then round up to next power of 2. */
-static unsigned max_zone_bits(struct tdb_context *tdb)
-{
- return fls64(tdb->map_size-1-sizeof(struct tdb_header)-1) + 1;
-}
-
-/* Start by using a random zone to spread the load: returns the offset. */
-static uint64_t random_zone(struct tdb_context *tdb)
-{
- struct free_zone_header zhdr;
- tdb_off_t off = sizeof(struct tdb_header);
- tdb_len_t half_bits;
- uint64_t randbits = 0;
- unsigned int i;
-
- for (i = 0; i < 64; i += fls64(RAND_MAX))
- randbits ^= ((uint64_t)random()) << i;
-
- /* FIXME: Does this work? Test! */
- half_bits = max_zone_bits(tdb) - 1;
- do {
- /* Pick left or right side (not outside file) */
- if ((randbits & 1)
- && !tdb->methods->oob(tdb, off + (1ULL << half_bits)
- + sizeof(zhdr), true)) {
- off += 1ULL << half_bits;
- }
- randbits >>= 1;
-
- if (tdb_read_convert(tdb, off, &zhdr, sizeof(zhdr)) == -1)
- return TDB_OFF_ERR;
-
- if (zhdr.zone_bits == half_bits)
- return off;
-
- half_bits--;
- } while (half_bits >= INITIAL_ZONE_BITS);
-
- tdb->ecode = TDB_ERR_CORRUPT;
- tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
- "random_zone: zone at %llu smaller than %u bits?",
- (long long)off, INITIAL_ZONE_BITS);
- return TDB_OFF_ERR;
-}
-
-int tdb_zone_init(struct tdb_context *tdb)
+int tdb_flist_init(struct tdb_context *tdb)
{
- tdb->zone_off = random_zone(tdb);
- if (tdb->zone_off == TDB_OFF_ERR)
- return -1;
- if (tdb_read_convert(tdb, tdb->zone_off,
- &tdb->zhdr, sizeof(tdb->zhdr)) == -1)
+ tdb->flist_off = tdb_read_off(tdb,
+ offsetof(struct tdb_header, free_list));
+ if (tdb->flist_off == TDB_OFF_ERR)
return -1;
return 0;
}
-/* Where's the header, given a zone size of 1 << zone_bits? */
-static tdb_off_t zone_off(tdb_off_t off, unsigned int zone_bits)
-{
- off -= sizeof(struct tdb_header);
- return (off & ~((1ULL << zone_bits) - 1)) + sizeof(struct tdb_header);
-}
-
/* Offset of a given bucket. */
-/* FIXME: bucket can be "unsigned" everywhere, or even uint8/16. */
-tdb_off_t bucket_off(tdb_off_t zone_off, tdb_off_t bucket)
+tdb_off_t bucket_off(tdb_off_t flist_off, unsigned bucket)
{
- return zone_off
- + sizeof(struct free_zone_header)
+ return flist_off + offsetof(struct tdb_freelist, buckets)
+ bucket * sizeof(tdb_off_t);
}
static tdb_off_t find_free_head(struct tdb_context *tdb, tdb_off_t bucket)
{
/* Speculatively search for a non-zero bucket. */
- return tdb_find_nonzero_off(tdb, bucket_off(tdb->zone_off, 0),
- bucket,
- BUCKETS_FOR_ZONE(tdb->zhdr.zone_bits) + 1);
+ return tdb_find_nonzero_off(tdb, bucket_off(tdb->flist_off, 0),
+ bucket, TDB_FREE_BUCKETS);
}
/* Remove from free bucket. */
static int remove_from_list(struct tdb_context *tdb,
- tdb_off_t b_off, struct tdb_free_record *r)
+ tdb_off_t b_off, tdb_off_t r_off,
+ struct tdb_free_record *r)
{
tdb_off_t off;
} else {
off = r->prev + offsetof(struct tdb_free_record, next);
}
+
+#ifdef DEBUG
+ if (tdb_read_off(tdb, off) != r_off) {
+ tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+ "remove_from_list: %llu bad prev in list %llu\n",
+ (long long)r_off, (long long)b_off);
+ return -1;
+ }
+#endif
+
/* r->prev->next = r->next */
if (tdb_write_off(tdb, off, r->next)) {
return -1;
if (r->next != 0) {
off = r->next + offsetof(struct tdb_free_record, prev);
/* r->next->prev = r->prev */
+
+#ifdef DEBUG
+ if (tdb_read_off(tdb, off) != r_off) {
+ tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+ "remove_from_list: %llu bad list %llu\n",
+ (long long)r_off, (long long)b_off);
+ return -1;
+ }
+#endif
+
if (tdb_write_off(tdb, off, r->prev)) {
return -1;
}
return -1;
if (new->next) {
+#ifdef DEBUG
+ if (tdb_read_off(tdb,
+ new->next
+ + offsetof(struct tdb_free_record, prev))
+ != 0) {
+ tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+ "enqueue_in_free: %llu bad head prev %llu\n",
+ (long long)new->next, (long long)b_off);
+ return -1;
+ }
+#endif
/* next->prev = new. */
if (tdb_write_off(tdb, new->next
+ offsetof(struct tdb_free_record, prev),
/* List need not be locked. */
int add_free_record(struct tdb_context *tdb,
- unsigned int zone_bits,
tdb_off_t off, tdb_len_t len_with_header)
{
struct tdb_free_record new;
int ret;
assert(len_with_header >= sizeof(new));
- assert(zone_bits < (1 << 6));
- new.magic_and_meta = TDB_FREE_MAGIC | zone_bits;
+ new.magic_and_meta = TDB_FREE_MAGIC;
new.data_len = len_with_header - sizeof(struct tdb_used_record);
- b_off = bucket_off(zone_off(off, zone_bits),
- size_to_bucket(zone_bits, new.data_len));
+ b_off = bucket_off(tdb->flist_off, size_to_bucket(new.data_len));
if (tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT) != 0)
return -1;
return ret;
}
+static size_t adjust_size(size_t keylen, size_t datalen)
+{
+ size_t size = keylen + datalen;
+
+ if (size < TDB_MIN_DATA_LEN)
+ size = TDB_MIN_DATA_LEN;
+
+ /* Round to next uint64_t boundary. */
+ return (size + (sizeof(uint64_t) - 1ULL)) & ~(sizeof(uint64_t) - 1ULL);
+}
+
/* If we have enough left over to be useful, split that off. */
-static int to_used_record(struct tdb_context *tdb,
- unsigned int zone_bits,
- tdb_off_t off,
- tdb_len_t needed,
- tdb_len_t total_len,
- tdb_len_t *actual)
+static size_t record_leftover(size_t keylen, size_t datalen,
+ bool want_extra, size_t total_len)
{
- struct tdb_used_record used;
- tdb_len_t leftover;
+ ssize_t leftover;
- leftover = total_len - needed;
- if (leftover < sizeof(struct tdb_free_record))
- leftover = 0;
+ if (want_extra)
+ datalen += datalen / 2;
+ leftover = total_len - adjust_size(keylen, datalen);
- *actual = total_len - leftover;
+ if (leftover < (ssize_t)sizeof(struct tdb_free_record))
+ return 0;
- if (leftover) {
- if (add_free_record(tdb, zone_bits,
- off + sizeof(used) + *actual,
- total_len - needed))
- return -1;
- }
- return 0;
+ return leftover;
}
/* Note: we unlock the current bucket if we coalesce or fail. */
static int coalesce(struct tdb_context *tdb,
- tdb_off_t zone_off, unsigned zone_bits,
tdb_off_t off, tdb_off_t b_off, tdb_len_t data_len)
{
struct tdb_free_record pad, *r;
- tdb_off_t end = off + sizeof(struct tdb_used_record) + data_len;
+ tdb_off_t end;
+
+ end = off + sizeof(struct tdb_used_record) + data_len;
- while (end < (zone_off + (1ULL << zone_bits))) {
+ while (end < tdb->map_size) {
tdb_off_t nb_off;
/* FIXME: do tdb_get here and below really win? */
if (frec_magic(r) != TDB_FREE_MAGIC)
break;
- nb_off = bucket_off(zone_off,
- size_to_bucket(zone_bits, r->data_len));
+ /* FIXME: Use flist from record */
+ nb_off = bucket_off(tdb->flist_off,size_to_bucket(r->data_len));
/* We may be violating lock order here, so best effort. */
if (tdb_lock_free_bucket(tdb, nb_off, TDB_LOCK_NOWAIT) == -1)
break;
}
- if (remove_from_list(tdb, nb_off, r) == -1) {
+ if (unlikely(bucket_off(tdb->flist_off,
+ size_to_bucket(r->data_len))
+ != nb_off)) {
+ tdb_unlock_free_bucket(tdb, nb_off);
+ break;
+ }
+
+ if (remove_from_list(tdb, nb_off, end, r) == -1) {
tdb_unlock_free_bucket(tdb, nb_off);
goto err;
}
goto err;
}
- if (remove_from_list(tdb, b_off, r) == -1)
+ if (remove_from_list(tdb, b_off, off, r) == -1)
+ goto err;
+
+ r = tdb_access_write(tdb, off, sizeof(*r), true);
+ if (!r)
+ goto err;
+
+ /* We have to drop this to avoid deadlocks, so make sure record
+ * doesn't get coalesced by someone else! */
+ r->magic_and_meta = TDB_COALESCING_MAGIC;
+ r->data_len = end - off - sizeof(struct tdb_used_record);
+ if (tdb_access_commit(tdb, r) != 0)
goto err;
- /* We have to drop this to avoid deadlocks. */
tdb_unlock_free_bucket(tdb, b_off);
- if (add_free_record(tdb, zone_bits, off, end - off) == -1)
+ if (add_free_record(tdb, off, end - off) == -1)
return -1;
return 1;
/* We need size bytes to put our key and data in. */
static tdb_off_t lock_and_alloc(struct tdb_context *tdb,
- tdb_off_t zone_off,
- unsigned zone_bits,
+ tdb_off_t flist_off,
tdb_off_t bucket,
- size_t size,
- tdb_len_t *actual)
+ size_t keylen, size_t datalen,
+ bool want_extra,
+ unsigned hashlow)
{
tdb_off_t off, b_off,best_off;
struct tdb_free_record pad, best = { 0 }, *r;
double multiplier;
+ size_t size = adjust_size(keylen, datalen);
again:
- b_off = bucket_off(zone_off, bucket);
+ b_off = bucket_off(flist_off, bucket);
- /* FIXME: Try non-blocking wait first, to measure contention.
- * If we're contented, try switching zones, and don't enlarge zone
- * next time (we want more zones). */
+ /* FIXME: Try non-blocking wait first, to measure contention. */
/* Lock this bucket. */
if (tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT) == -1) {
return TDB_OFF_ERR;
best.data_len = -1ULL;
best_off = 0;
- /* FIXME: Start with larger multiplier if we're growing. */
- multiplier = 1.0;
+
+ /* Get slack if we're after extra. */
+ if (want_extra)
+ multiplier = 1.5;
+ else
+ multiplier = 1.0;
/* Walk the list to see if any are large enough, getting less fussy
* as we go. */
}
if (best.data_len < size * multiplier && best_off)
- goto use_best;
+ break;
multiplier *= 1.01;
/* Since we're going slow anyway, try coalescing here. */
- switch (coalesce(tdb, zone_off, zone_bits, off, b_off,
- r->data_len)) {
+ switch (coalesce(tdb, off, b_off, r->data_len)) {
case -1:
/* This has already unlocked on error. */
return -1;
/* If we found anything at all, use it. */
if (best_off) {
- use_best:
+ struct tdb_used_record rec;
+ size_t leftover;
+
/* We're happy with this size: take it. */
- if (remove_from_list(tdb, b_off, &best) != 0)
+ if (remove_from_list(tdb, b_off, best_off, &best) != 0)
+ goto unlock_err;
+
+ leftover = record_leftover(keylen, datalen, want_extra,
+ best.data_len);
+
+ assert(keylen + datalen + leftover <= best.data_len);
+ /* We need to mark non-free before we drop lock, otherwise
+ * coalesce() could try to merge it! */
+ if (set_header(tdb, &rec, keylen, datalen,
+ best.data_len - leftover,
+ hashlow) != 0)
goto unlock_err;
+
+ if (tdb_write_convert(tdb, best_off, &rec, sizeof(rec)) != 0)
+ goto unlock_err;
+
tdb_unlock_free_bucket(tdb, b_off);
- if (to_used_record(tdb, zone_bits, best_off, size,
- best.data_len, actual)) {
- return -1;
+ if (leftover) {
+ if (add_free_record(tdb,
+ best_off + sizeof(rec)
+ + best.data_len - leftover,
+ leftover))
+ return TDB_OFF_ERR;
}
return best_off;
}
return TDB_OFF_ERR;
}
-static bool next_zone(struct tdb_context *tdb)
-{
- tdb_off_t next = tdb->zone_off + (1ULL << tdb->zhdr.zone_bits);
-
- /* We must have a header. */
- if (tdb->methods->oob(tdb, next + sizeof(tdb->zhdr), true))
- return false;
-
- tdb->zone_off = next;
- return tdb_read_convert(tdb, next, &tdb->zhdr, sizeof(tdb->zhdr)) == 0;
-}
-
-/* Offset returned is within current zone (which it may alter). */
-static tdb_off_t get_free(struct tdb_context *tdb, size_t size,
- tdb_len_t *actual)
+/* Get a free block from current free list, or 0 if none. */
+static tdb_off_t get_free(struct tdb_context *tdb,
+ size_t keylen, size_t datalen, bool want_extra,
+ unsigned hashlow)
{
- tdb_off_t start_zone = tdb->zone_off, off;
- bool wrapped = false;
-
- /* FIXME: If we don't get a hit in the first bucket we want,
- * try changing zones for next time. That should help wear
- * zones evenly, so we don't need to search all of them before
- * expanding. */
- while (!wrapped || tdb->zone_off != start_zone) {
- tdb_off_t b;
-
- /* Shortcut for really huge allocations... */
- if ((size >> tdb->zhdr.zone_bits) != 0)
- continue;
-
- /* Start at exact size bucket, and search up... */
- b = size_to_bucket(tdb->zhdr.zone_bits, size);
- for (b = find_free_head(tdb, b);
- b <= BUCKETS_FOR_ZONE(tdb->zhdr.zone_bits);
- b += find_free_head(tdb, b + 1)) {
- /* Try getting one from list. */
- off = lock_and_alloc(tdb, tdb->zone_off,
- tdb->zhdr.zone_bits,
- b, size, actual);
- if (off == TDB_OFF_ERR)
- return TDB_OFF_ERR;
- if (off != 0)
- return off;
- /* Didn't work. Try next bucket. */
- }
-
- /* Didn't work, try next zone, if it exists. */
- if (!next_zone(tdb)) {
- wrapped = true;
- tdb->zone_off = sizeof(struct tdb_header);
- if (tdb_read_convert(tdb, tdb->zone_off,
- &tdb->zhdr, sizeof(tdb->zhdr))) {
- return TDB_OFF_ERR;
- }
- }
+ tdb_off_t off;
+ unsigned start_b, b;
+
+ /* If they are growing, add 50% to get to higher bucket. */
+ if (want_extra)
+ start_b = size_to_bucket(adjust_size(keylen,
+ datalen + datalen / 2));
+ else
+ start_b = size_to_bucket(adjust_size(keylen, datalen));
+
+ /* Start at exact size bucket, and search up... */
+ for (b = find_free_head(tdb, start_b);
+ b < TDB_FREE_BUCKETS;
+ b = find_free_head(tdb, b + 1)) {
+ /* Try getting one from list. */
+ off = lock_and_alloc(tdb, tdb->flist_off,
+ b, keylen, datalen, want_extra,
+ hashlow);
+ if (off == TDB_OFF_ERR)
+ return TDB_OFF_ERR;
+ if (off != 0)
+ return off;
+ /* Didn't work. Try next bucket. */
}
return 0;
}
int set_header(struct tdb_context *tdb,
struct tdb_used_record *rec,
uint64_t keylen, uint64_t datalen,
- uint64_t actuallen, uint64_t hash,
- unsigned int zone_bits)
+ uint64_t actuallen, unsigned hashlow)
{
uint64_t keybits = (fls64(keylen) + 1) / 2;
/* Use bottom bits of hash, so it's independent of hash table size. */
- rec->magic_and_meta
- = zone_bits
- | ((hash & ((1 << 5)-1)) << 6)
+ rec->magic_and_meta = (hashlow & ((1 << 11)-1))
| ((actuallen - (keylen + datalen)) << 11)
| (keybits << 43)
| (TDB_MAGIC << 48);
return 0;
}
-static bool zones_happy(struct tdb_context *tdb)
-{
- /* FIXME: look at distribution of zones. */
- return true;
-}
-
-/* Assume we want buckets up to the comfort factor. */
-static tdb_len_t overhead(unsigned int zone_bits)
-{
- return sizeof(struct free_zone_header)
- + (BUCKETS_FOR_ZONE(zone_bits) + 1) * sizeof(tdb_off_t);
-}
-
-/* Expand the database (by adding a zone). */
+/* Expand the database. */
static int tdb_expand(struct tdb_context *tdb, tdb_len_t size)
{
uint64_t old_size;
- tdb_off_t off;
- uint8_t zone_bits;
- unsigned int num_buckets;
tdb_len_t wanted;
- struct free_zone_header zhdr;
- bool enlarge_zone;
/* We need room for the record header too. */
wanted = sizeof(struct tdb_used_record) + size;
/* Someone else may have expanded the file, so retry. */
old_size = tdb->map_size;
tdb->methods->oob(tdb, tdb->map_size + 1, true);
- if (tdb->map_size != old_size)
- goto success;
-
- /* FIXME: Tailer is a bogus optimization, remove it. */
- /* zone bits tailer char is protected by EXPAND lock. */
- if (tdb->methods->read(tdb, old_size - 1, &zone_bits, 1) == -1)
- goto fail;
-
- /* If zones aren't working well, add larger zone if possible. */
- enlarge_zone = !zones_happy(tdb);
-
- /* New zone can be between zone_bits or larger if we're on the right
- * boundary. */
- for (;;) {
- /* Does this fit the allocation comfortably? */
- if ((1ULL << zone_bits) >= overhead(zone_bits) + wanted) {
- /* Only let enlarge_zone enlarge us once. */
- if (!enlarge_zone)
- break;
- enlarge_zone = false;
- }
- if ((old_size - 1 - sizeof(struct tdb_header))
- & (1 << zone_bits))
- break;
- zone_bits++;
+ if (tdb->map_size != old_size) {
+ tdb_unlock_expand(tdb, F_WRLCK);
+ return 0;
}
- zhdr.zone_bits = zone_bits;
- num_buckets = BUCKETS_FOR_ZONE(zone_bits);
-
- /* FIXME: I don't think we need to expand to full zone, do we? */
- if (tdb->methods->expand_file(tdb, 1ULL << zone_bits) == -1)
- goto fail;
-
- /* Write new tailer. */
- if (tdb->methods->write(tdb, tdb->map_size - 1, &zone_bits, 1) == -1)
- goto fail;
-
- /* Write new zone header (just before old tailer). */
- off = old_size - 1;
- if (tdb_write_convert(tdb, off, &zhdr, sizeof(zhdr)) == -1)
- goto fail;
-
- /* Now write empty buckets. */
- off += sizeof(zhdr);
- if (zero_out(tdb, off, (num_buckets+1) * sizeof(tdb_off_t)) == -1)
- goto fail;
- off += (num_buckets+1) * sizeof(tdb_off_t);
-
- /* Now add the rest as our free record. */
- if (add_free_record(tdb, zone_bits, off, tdb->map_size-1-off) == -1)
- goto fail;
-
- /* Try allocating from this zone now. */
- tdb->zone_off = old_size - 1;
- tdb->zhdr = zhdr;
+ if (tdb->methods->expand_file(tdb, wanted*TDB_EXTENSION_FACTOR) == -1) {
+ tdb_unlock_expand(tdb, F_WRLCK);
+ return -1;
+ }
-success:
+ /* We need to drop this lock before adding free record. */
tdb_unlock_expand(tdb, F_WRLCK);
- return 0;
-fail:
- tdb_unlock_expand(tdb, F_WRLCK);
- return -1;
-}
-
-static tdb_len_t adjust_size(size_t keylen, size_t datalen, bool growing)
-{
- tdb_len_t size = keylen + datalen;
-
- if (size < TDB_MIN_DATA_LEN)
- size = TDB_MIN_DATA_LEN;
-
- /* Overallocate if this is coming from an enlarging store. */
- if (growing)
- size += datalen / 2;
-
- /* Round to next uint64_t boundary. */
- return (size + (sizeof(uint64_t) - 1ULL)) & ~(sizeof(uint64_t) - 1ULL);
+ return add_free_record(tdb, old_size, wanted * TDB_EXTENSION_FACTOR);
}
/* This won't fail: it will expand the database if it has to. */
uint64_t hash, bool growing)
{
tdb_off_t off;
- tdb_len_t size, actual;
- struct tdb_used_record rec;
/* We can't hold pointers during this: we could unmap! */
assert(!tdb->direct_access);
- size = adjust_size(keylen, datalen, growing);
-
-again:
- off = get_free(tdb, size, &actual);
- if (unlikely(off == TDB_OFF_ERR))
- return off;
+ for (;;) {
+ off = get_free(tdb, keylen, datalen, growing, hash);
+ if (likely(off != 0))
+ break;
- if (unlikely(off == 0)) {
- if (tdb_expand(tdb, size) == -1)
+ if (tdb_expand(tdb, adjust_size(keylen, datalen)))
return TDB_OFF_ERR;
- goto again;
}
- /* Some supergiant values can't be encoded. */
- /* FIXME: Check before, and limit actual in get_free. */
- if (set_header(tdb, &rec, keylen, datalen, actual, hash,
- tdb->zhdr.zone_bits) != 0) {
- add_free_record(tdb, tdb->zhdr.zone_bits, off,
- sizeof(rec) + actual);
- return TDB_OFF_ERR;
- }
-
- if (tdb_write_convert(tdb, off, &rec, sizeof(rec)) != 0)
- return TDB_OFF_ERR;
-
return off;
}
projects / ccan / blobdiff